ball joints, top?

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bzrse7en
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Re: ball joints, top?

Post by bzrse7en » Mon May 08, 2017 5:32 pm

7dreamer wrote:First off i will say i know the status quo works and works well and has done on thousands of lotus 7 type cars. I had a discussion with a certifier after i saw the drama 7ish had on his McGregor build and I wanted some clarification for my own very slow build.
I am using holden gemini uprights so in a slightly different boat to most here. Currently I have toyota tie rod ends which I'm unhappy with. By pure chance honda civic top ball joints work for me and a quick search of tradme will show that the tuner market has made a ball joint that will allow camber adjustment so I will use these on a new set of a arms. It will depend on your certifier and there opinion of wat they find unacceptable. Simply a tie rod was never designed as a loaded suspension compoment to take vertical shock load they are designed to transfer lateral load to the upright and get dragged up and down by the suspension movement. Hope that makes some sense.
Pete.
Yea, but isn't the top BJ only loaded latterally anyway? (normal seven configuration). If I remember correctly, the McG suspension in question had a pull rod system, therefore loaded differently.
The failures I have seen (not many) were the thread bending on Valiant tie rods (9/16" UNF) when driven into things. Caterham use Lada (M16x1) Lotus used Vanguard (5/8" UNF) on most cars inc race cars and Locosts are M18x1.5, so they are all stronger in the thread area.

7dreamer
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Re: ball joints, top?

Post by 7dreamer » Mon May 08, 2017 6:28 pm

It's not so much the thread size the certifier was worried about it was the actual design of a tie rod compared to ball joint. And there ability to withstand unexpected road hazards pot holes etc. I think it all stems from a fatal trike accident which was attributed to a failed tie rod end which was used as a ball joint. I talked to him about spherical bearings and he certainly wasn't a fan of them either. Again they are not designed to handle the shock loads of road driving. Like I said though talk to the certifier you're using and figure out what they want.

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7ish
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Re: ball joints, top?

Post by 7ish » Mon May 08, 2017 6:32 pm

Spherical bearings can't pull out like a ball joint...they have a bolt through them.
7ish

7dreamer
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Re: ball joints, top?

Post by 7dreamer » Mon May 08, 2017 7:46 pm

To me a spherical bearing is the easiest non ball joint option and I would like to use them .... but I know my certifier dosnt like them so there's pretty much no point in trying too. All certifiers are different. Good or bad it's them we have to work with.

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steveb
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Re: ball joints, top?

Post by steveb » Thu May 11, 2017 12:33 pm

rod ends were acceptable if of "premium quality" and not loaded ie not supporting the sprung weight of the suspension,
well that was in the hot rod hobby manual, may it has changed. rod end had to be secured by "a larger than rod" retainer (washer arrangement).
perhaps a taper pin setup to accept a rod end and mate to the upright taper, if that makes sense?

bzrse7en
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Re: ball joints, top?

Post by bzrse7en » Thu May 11, 2017 2:07 pm

Can't see how a single accident / failure can have this much effect on the whole home built clubbie activity nation wide.
My 23 was only certed recently, with Lada tie rods as top joints.
I still cannot see much difference in the loading of an unloaded top BJ on a light car and a tie rod / drag link end from a heavy van when hitting a pothole.

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steveb
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Re: ball joints, top?

Post by steveb » Thu May 11, 2017 2:39 pm

Thanks Patrick, that s pretty much what the certifier told me over 10 years ago.
No idea if he is still in business.

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